In line illumination systems a large number of luminaires are typically arranged in a row in one longitudinal direction. Traditional TL-lighting systems (tubular fluorescent lamp systems) make use of a trunking system to attach the TL-luminaires. These systems can be ceiling mounted or suspended from the ceiling using wires. The trunking system typically contains cabling. A known TL-luminaire suitable for line illumination is shown in EP 0828 114 A2, which discloses a luminaire for line illumination having a light carrier arranged with means projecting downwards from the light carrier having two connectors for electrically and mechanically engaging a TL-lamp on opposite sides thereof, a trunk shaped carrier to which the light carrier is mounted, and a reflector for beaming the light generated by the TL-lamp. The reflector is attached to the light carrier, and is further arranged having a coupling member projecting into a reflector of an adjacent luminaire when mounted in a line illumination system, to nest adjacent reflectors together. Assembly of such a known line illumination system requires a large number of mounting steps, and further requires several steps to access the light carrier.
Further, as LED based lighting devices, or LED lamps, have become common on the market, and are showing great promise to gradually replace incandescent and compact fluorescent lamps throughout the world due to long life-time expectancy, reduced size and weight, and high energy-efficiency with respect to energy and lumen output efficiency as compared to for instance traditional TL-tube lighting, it is desirable to provide LED based line illumination systems. Retrofit LED TL-lamps are available on the market today, which are applicable in existing TL-luminaire line illumination systems. However, replacing the TL-lamp with a retrofit LED TL-lamp in the known TL-luminaire above does not overcome the draw backs as described above.